Difluorophosphoric acid is an inorganic compound with the formula HPO2F2.

It is a mobile colorless strongly fuming liquid.

[1] The acid has limited applications, in part because it is thermally and hydrolytically unstable.

[3] Difluorophosphoric acid is corrosive to glass, fabric, metals and living tissue.

[1] A method to make pure difluorphosphoric acid involves heating phosphoryl fluoride with fluorophosphoric acid and separating the product by distillation:[4] It is prepared by hydrolysis of phosphoryl fluoride: Further hydrolysis gives fluorophosphoric acid: Complete hydrolysis gives phosphoric acid: The salts of difluorophosphoric acid are known as difluorophosphates.